Tube flaring machine



Nov. ll, 1969 J, E, SzlTAR, JR 3,477,265

TUBE FLARING MACHINE Filed Sept. 1967 5 Sheets-Sheet l Nov. l1, 1969 J. E. szlTAR, .1R

TUBE FLARING MACHINE 5 Sheets-Sheet 2 Filed Sept. 1967 NOV. 11, 1969 l J, E SzlTAR,` JR 3,477,265

TUBE FLARING MACHINE Filed Sept. 5, 1967 5 Sheets-Sheet Arma/Vir;

NOV- 11, 1969 J. E. szlTAR, .1R

TUBE FLARING MACHINE 5 Sheets-Sheet 4 Filed Sept.

ANN

Nov. l1, 1969 J. E. szrrAR, JR

TUBE FLAHING MACHINE 5 Shets-Sheet 5 .lvllllllqmwxlg.

United States Patent Y() M 3,477,265 TUBE FLARING MACHINE `l'ohn E. Szitar, Jr., Cleveland Heights, Ohio, assignor to Teledyne, Inc., Gardena, Calif., a corporation of Delaware Filed Sept. 5, 1967, Ser. No. 665,502 Int. Cl. B21d 41/02 U.S. Cl. 72-117 20 Claims ABSTRACT F THE DISCLOSURE This disclosure describes a tube flaring machine which may include a die for receiving the tube and a flaring tool for cooperating with the die to are the tube. The force applied by the flaring tool to the tube can be regulated and adjusted so that the flared portion of the tube has smooth surfaces and is of uniform wall thickness. Preferably, the aring tool is moved radially outwardly in a controlled fashion by a variable speed electric motor.

BACKGROUND OF THE INVENTION As is well known, tube flaring in-volves deforming an end portion of a tube radially outwardly at the desired angle. Flared tubes have many uses, such as in the aerospace industry, which require that the wall thickness of the ared portion of the tube be uniform and that the flared portion have smooth wall surfaces.

The conventional tube aring machine uses an annular die for receiving the tube. The die has an appropriately shaped flaring surface surrounding the end portion of the tube. A aring tool or flaring cone is mounted adjacent the die and extends into the interior of the end portion of the tube. The aring tool and/or die are then moved to cause the flaring tool to force the wall of the tube radially outwardly against the flaring surface. Typically, the Haring tool is moved radially outwardly to forcibly contact the interior surface of the tube wall to apply a radial outward force thereagainst whi-ch deforms the wall. Simultaneously, the flaring tool and die are appropriately rotated relative to each other so that the radial force is applied to a circumferentially extending zone of the tube.

One problem with this prior art structure is that the aring cone is moved rapidly radially outwardly with substantial force. Thus, the flaring tool rapidly applies a high magnitude force against the tube wall. This shock loading of the tube wall not infrequently results in excessive thinning of the ared wall of the tube which renders the tube useless for its intended purposes. Oftentimes, the ared portion of the tube fails or is severed from the remainder of the tube as a result of this high magnitude force. These problems are particularly acute when the tube is thin-walled or of small diameter, 0r constructed of relatively soft material. Furthermore, this prior art tube llaring machine as described above is totally unsuited for use in flaring tubes that are constructed of brittle material.

Typically, the die is connected to the structure for supporting the flaring tool, Thus, the relative radial position of the Haring tool and die are xed. 'Ihe tubes to be ilared are, of course, built within certain allowable tolerances. Although iixing the position of the die and aring t-ool is 3,477,265 Patented Nov. 11, 1969 ICC satisfactory for some of the tubes, it has been found that tubes constructed near the high side or low side of the allowable tolerance range are oftentimes not ared as precisely as desired because of this iixed die-to-flaring tool position.

To properly flare the tube, it is essential that the tube project into the die a predetermined amount. Heretofore, such measurement has been made by a fairly complex system which takes an excessive amount of time to operate.

SUMMARY OF THE INVENTION The present invention teaches that tubes having a smooth flared wall of uniform wall thickness can be produced by regulating the force and speed of movement of the flaring tool toward the die. More particularly, the present invention teaches that the force applied by the flaring tool to the tube wall should be gradually increased to cause the tube wall to be gradually deformed. It has been found that these improved results are consistently obtained on virtually all tubes including small diameter tubes, thin-walled tubes, and tubes constructed of soft material such as aluminum. Furthermore, appropriate application of these teachings of this invention permit flaring of a tube constructed of a brittle material. Thus, the present invention achieves results which were heretofore not attainable.

The present invention may be embodied in a Haring machine which includes a die having an opening therein for receiving an end portion of the tube to be ared and a aring surface generally radially outwardly of the end portion of the tube. A Haring tool is mounted adjacent the die and projects into the interior of the end portion of the tube.

According to a preferred practice of the invention, the flaring tool is moved radially outwardly into contact with the interior wall surface of the tube to apply a force thereto, and thereafter, the force supplied to the tube Wall is gradually increased to gradually flare the tube. Simultaneously, the flaring tool and die are appropriately rotated relative to each other so that the radial outward movement of the flaring tool will operate to gradually deform the end portion of the tube in a circumferential zone.

The magnitude of the force applied by the aring tool and the rate of increase thereof can be appropriately adjusted to suit tubes of different diameters, wall thickness, material, etc. By way of example, the daring tool may be moved radially outwardly with increasing force for a period of about 8 seconds.

The present invention also teaches that optimum results are obtained in increasing the force applied by the flaring tool up to a maximum, and thereafter maintaining such maximum force for a predetermined period of time designated herein as dwell time. By way of example, the dwell time may be of the order of 2 seconds. During the dwell time the flaring tool and the die set the are to eliminate or substantially reduce the tendency of the tube to spring back, i.e. to move toward its original position under the influence of its inherent resiliency. Generally, the dwell time does not operate to materially additionally bend the material of the tube toward the flared position, but merely operates to set the already flared end portion in the desired flared position.

n The flaring tool must be appropriately mounted to permit movement thereof generally radially outwardly toward the flaring surface of the die. Preferably, the flaring tool is mounted in a rotatable head and is movable radially outwardly therein under the influence of one or more centrifugal weights. Although the radial movement of the flaring tool could be controlled independently of the rotational speed of the head, use of the centrifugal weights is preferred because rotation of the head serves the dual functions of rotating the flaring tool to flare the tube and operating the centrifugal weights to urge the flaring tool radially outwardly. Preferably a stop is provided in the head to positively prevent radial outward movement of the flaring tool beyond a predetermined amount.

According to the present invention, the head is drivingly connected to an electric motor which rotates the head and the flaring tool. It is apparent that the force applied by the centrifugal weights tending to move the flaring tool outwardly is a function of the speed of rotation of the head which in turn is a function of the speed of rotation of the electric motor. Accordingly, the present invention teaches controlling the rotational speed of the electric motor with suitable speed control means to thereby control the magnitude of the radial outward force applied by the flaring tool to the tube. As it is desired to gradually increase the magnitude of the radial force applied to the tube, the speed control means should be capable of gradually increasing the speed of the electric motor. Of course, when electric current is supplied to an electric motor, the speed thereof does not immediately and instantaneously increase from zero to the operating speed. Reference herein to gradual increase of motor speed does not include this rapid normal acceleration of any electric motor from zero to its operating speed. An electric motor might ordinarily be brought from zero r.p.m. to full speed in less than one second whereas the gradual speed increase referred to herein is longer than that period of time, and, as indicated earlier, may be of the order of about 8 seconds; however, the length of time may be varied to suit the particular requirements of the flaring operation.

The speed control means are preferably electrical and desirably permit adjustment of the rate of acceleration of the electric motor to thereby permit adjustment of the rate of increase of the radial force which is applied to the tube. The speed control means should also permit adjusting of the maximum speed of the motor to thereby permit adjustment of the maximum force applied by the flaring tool to the tube. The present invention also teaches that the speed control means should provide for operation of the electric motor at a minimum speed during installation and removal of the tube from the flaring machine to thereby obviate the need for repeated motor start-up for each tube and to minimize the amount of acceleration which the motor must undergo for each tube. Preferably, clutch means should be provided for drivingly disconnecting the head from the motor when the motor is running at minimum speed to thereby facilitate setup of the machine. The minimum speed should be adjusted to permit easy engagement of the clutch and to prevent excessively rapid radial movement of the flaring tool when the clutch is engaged.

The speed control means for accomplishing all of these diverse and desirable functions can be of various designs; however, it is preferred to provide a second motor and means driven by the second motor for gradually increasing the speed of the first motor, i.e. the motor which drives the head. It has been found that utilizing the second motor to drive a wiper of a potentiometer which in turn produces a speed control signal for the first motor is quite effective.

The present invention also eliminates the problem mentioned hereinabove concerning high side and low side tolerance tubes. This desirable function is quickly and easily accomplished by aflixing the die to the head in a manner to permit relative radial movement therebetween.

Adjusting the position of the die relative to the head with removable stops compensates for high side or low side tolerances of the tubes.

The present invention also provides tube holding means or a vise movable between an operative position in which the tube is inserted within the die and an inoperative position in which the tube is withdrawn from the die. A feature of this invention is the provision of an adjustable stop or stop gauge on the tube holding means for rapidly and accurately measuring the amount that the tube will project into the die when the tube holding means is in the operative position. A micrometer is also mounted on the tube holding means for controlling the position of the adjustable stop.

The invention, both as to its organization and method of operation together with further features and advantages thereof may best be understood by reference to the following description taken in connection with the accompanying illustrative drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. l is a schematic block diagram of the several components of a tube flaring machine constructed in accordance with the teachings of this invention.

FIG. 2 is a fragmentary perspective view of the tube flaring machine.

FIG. 3 is an enlarged fragmentary sectional view taken generally along line 3-3 of FIG. 4 and showing the die and head of the flaring machine.

FIG. 4 is an elevational view partially in section taken along line 4-4 of FIG. 3.

FIG. 5 is a sectional view taken generally along line 5-5 of FIG. 3.

FIG. 5a is a fragmentary sectional view showing a detail of one of the centrifugal weights.

FIG. 6 is a plan view showing the tube holding means and the stop gauge.

FIG. 7 is a schematic view of the tube flaring machine andthe electrical controls therefor.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings and in particular to FIGS. l and 2 thereof, reference numeral 11 designates a tube flaring machine constructed in accordance with the teachings of this invention. As shown diagrammatically in FIG. l, the tube flaring machine includes tube flaring equipment 13 which serves to mechanically carry out the flaring operation. The tube flaring equipment is driven by a motor M-1 through a drive shaft or spindle 15. A clutch 17 and a brake 19 are interposed in the drive shaft 15 to allow for drivingly disconnecting the motor M-1 from the flaring equipment 13 and for stopping the rotation of the flaring equipment 13, respectively. The speed of the motor M-1 is controlled by a speed controller 21 which also controls the operation of the clutch 17 and the brake 19.

FIG. 2 illustrates generally how the various portions of the tube flaring machine may be physically embodied. Thus, the tube flaring machine 11 may include a suitable table or support 23 on which a housing 25 and a track 27 are suitably mounted. The motor M-l, the clutch 1'7, the brake 19, and the necessary conventional accessory elements for the drive shaft 15 may be suitably encased within the housing 25 and/or within a housing 29 which surrounds and forms a portion of the table 23.

Generally, the tube flaring equipment 13 includes a head 31 and a die assembly 33 mounted in a manner described hereinbelow. The tube flaring equipment 13 also includes a tube holder 35 mounted on the track 27 for sliding movement toward and away from the head 31. A crank 36 may lbe turned to move the tube holder 35 toward and away from the die assembly 33 in a conventional manner. The tube holder 35, which is also described in more detail hereinbelow, serves to mount a tube 37 (FIG. 3) in a conventional manner. Thus, the tube holder 35 acts as a vise to retain the tube 37 during the flaring operation. The tube holder 35 may be caused to grip or release the tube 37 in a conventional manner in response to turning of an operating wheel 38. `Once the tube 37 is mounted in the tube holder 35, the portion thereof which is to be flared can be inserted within the die 33 by appropriately turning the crank 36 to move the tube holder 35 toward the head 33. Preferably, the movement of the tube holder 35 toward the head 33 is limited Iby a conventional stop (not shown).

Turning now to the details of the preferred embodiment, FIGS. 3-5 show the details of the head 31 and the die assembly 33. As best seen in FIG. 3, the head 31 is drivingly connected to one end of the drive shaft and the die assembly 33 is mounted on the opposite face of the head 31. More particularly, the head 31 includes a plate 39 which is secured to the drive shaft 15 by a plurality of fasteners 41. The head 31 also has a circumferential wall 43 which is mounted on the plate 39 in any suitable manner such as by fasteners 45. The die assembly 33 is mounted on the forward face 47 of the head 31 as shown in FIG. 4. A pair of rails 49 is affixed to the head 31 in spaced parallel relationship by fasteners 51. Each of the rails 49 has an overhanging flange 53 which retains the opposed edges of the die assembly 33 against the forward face 47 of the head 31.

The radial position of the die assembly 33 relative to the head 31 is adjustable. In the embodiment illustrated, the means for accomplishing this function includes a removable stop 55 mounted in a lug 57 on the head 31. The removable stop 55, when mounted on the llug 57 extends a fixed predetermined amount therebeyond and engages the adjacent edge 58 of the die assembly 33. A movable stop 59 is mounted within the lug 61 on the opposite side of the head 31 from the lug 57. The movable stop 59 can be threadedly mounted within the lug 61 and turned so as to cause the die assembly 33 to bear tightly against the removable stop 55. Thus, the rails 149 and the stops 55 and 59 operate to firmly mount the die assembly 33 on the head 31.

If it is desired to changethe position of the die assembly 33 relative to the head 31 as, for example, to compensate for high side or low side tolerances, the removable stop 55 is removed from the lug 57 and another stop, which is slightly longer or shorter than the removable stop 55, is inserted into the lug 57 and into engagement with the edge 5S of the die assembly 33. The new removable stop extends a different fixed predetermined amount beyond the lug 57 to thereby permit adjusting the position of the die assembly 33. The removable stop 59 is then loosened or tightened a-s may be necessary to cause the stops 55 and 59 to tightly grip the die in the new radial position thereof. The removable stop 55 and lug 57 can be of any suitable type which lwill permit the stop 55 to have a xed determined position once it is mounted within the lug 57.

As shown in FIGS. 3 and 5 a flaring tool 63 in the form of a flaring cone is rotatably mounted by a bearing 64 on a slidable rack I65 within the head 31. As shown in FIG. 3, the rack 65 has an inclined passage 67 therein into which an enlarged portion `69 of the flaring tool 63 is received. Although the rack 65 may be mounted in any suitable manner, in the embodiment illustrated, the rack 65 is slidably mounted between a pair of rails 71 (FIG. 5). The rack l65 has teeth 73 and 75 on opposite sides thereof and is slidable between a fixed abutment 72 and a movable abutment 72a.

The rack 65 is driven by a pair of centrifugal weights 75 and 77. The Weights 75 and 77 have gear portions 79 and 81, respectively, which mesh with pinions 83 and 85. The centrifugal lweights 75 and 77 are suitably mounted for pivotal movement within the head 31 by shafts 86 and 87, respectively, and the pinions 83 and 85 are similarly suitably mounted for rotation within the head. The head 31 may be appropriately provided with circumferentially extending slots to allow the centrifugal weights 75 and 77 to project therefrom and to allow the weights to pivot about their respective pivotal axes. As shown in FIG. 5, the pinion and the gear portion 79 mesh with the teeth 73 and 75, respectively, so that the pivotal movement of the centrifugal Weights 75 and 77 about their respective pivotal axes in -response to rotation of the head 31 tends to drive the rack 65 radially within the head.

It can be seen, therefore, that rotation of the head 31 causes these centrifugal weights 75 and 77 to pivot to- Iward the positions thereof shown in dashed lines in FIG. 5. Such pivotal movement drives the rack 65 and the flaring tool 63 upwardly as shown in FIG. 5. The velocity of the head 31 determines the force that is applied by the centrifugal weights 75 and 77 to tend to drive the flaring tool `63. The adjustable abutment 72a, which may be in the form of a threaded member mounted on the circumferential wall 43 of the head 31, limits the downward movement of the rack 65 as viewed in FIG. 5 and abutment 72 limits upward movement thereof.

Referring to FIG. 5a, the mass of the centrifugal weight 77 may be varied by inserting a weight 89 into an aperture 89a in the centrifugal weight. The Weight 8'9 may be retained in any suitable manner such as by set screw `90. Thus, by adding weight to the centrifugal weights 75 and 77, the force exerted by the flaring tool 63 on the tube 37 for a given r.p.m. of the head 31 can be changed.

The die assembly 33 includes a mounting block 91 (FIGS. 3 4), which is engaged by the stops 55 and 59, and a bearing 93 mounted in the mounting block 81 and retained therein by flanges 95 and .a retainer 97. The bearing 93 has an inner race 99 in which a sleeve 101 is retained by a retaining ring 103 and by a flange 105 integral with the sleeve. A die 107 is mounted within the sleeve 101 and suitably retained therein. The bearing 93 serves to mount the sleeve 101 and the die 107 for rotation relative to the mounting block 91 and the head 31. The die member 107 has a passageway 109 extending therethrough and terminating inwardly a flaring surface 111. In the embodiment illustrated, the flaring surface 111 has a frustoconical configuration. The tube holder 35 is operative to hold the tube 37 within the passageway 109 so that an end portion 113 of the tube lies radially within the flaring surface 111. The machine 11 is preferably of the orbital type .and accordingly, the die 107 is mounted for rotation about an axis which is eccentric to the axes of rotation for the head 31.

FIG. 6 illustrates another feature of the present invention in which the amount that the tube 37 will ultimately project into the die 107 is accurately measured and controlled. As shown in FIG. 6, the tube holder 35 includes a chuck 121 for mounting the tube 37 with the end portion 113 thereof projecting axially toward the die 107. As shown in FIG. 6, the tube holder 35 is holding the end portion 113 of the tube 37 4spaced axially from the die 107 and such position of the tube holder is designated herein as the retracted position.

The tube holder 35 also includes an axially extending shaft 123 which is biased to the right as viewed in FIG. 6 by `a spring 125. The axis of the shaft 123 is spaced laterally or radially from the axis of the tube 37. The shaft 123 is mounted for pivotal and axial movement about its longitudinal axis. Such movement of the shaft 123 can be effected by means of a lever 127 which is drivingly affixed to the shaft 123 and which projects upwardly through a slot 129 in a casing 131 for the shaft 123. The slot 129 has a long axial portion 133, a short axial portion 135, and a lateral portion 137 interconnecting the ends of the portions 133 and 135. Thus, by moving of the lever 127 as permitted by the slot 129, the shaft 123 can be pivoted and moved axially.

An adjustable stop or stop gauge 139 is mounted on the inner end of the shaft 133 for pivotal and axial movement therewith. The stop gauge 139 pivots and moves axially with the shaft 133 between the operative position shown in full lines in FIG. 6, and the retracted position shown in dashed lines in FIG. 6. A micrometer 141 is mounted to the stop gauge 139 intermediate the ends thereof. The micrometer 141 has an end 143 which engages a Calibrating surface 145 on the chuck 121 in the operative position thereof and a second calibrating surface 147, located on the tube holder 35, in the retracted position of the stop gauge 139. The stop gauge 139 also has a surface 149 for contacting the end of the tube 37 to adjust or set the axial position thereof.

In use of this portion of the tube flaring machine, the micrometer 141 is adjusted with the end 143 thereof contacting either of the Calibrating surfaces 145 or 147. As the micrometer 141 is affixed to the stop gauge 139, adjustment of the micrometer moves the stop gauge and the surface 149 thereof axially. When the micrometer 141 has been set, the stop gauge 139 is moved with the lever 127 to the operative position (if the stop gauge was calibrated in the retracted position) and the tube 37 is moved axially within the chuck 121 until the end thereof engages the surface 149 at which time the wheel 38 is turned to cause the chuck to firmly and rigidly grip the tube 37. By appropriate manipulation of the lever 127 the stop gauge 139 is then moved to the retracted position and the crank 36 is turned to move the tube holder 35 to its operative position in which the end portion 113 of the tube is received within the die 107 as shown in FIG. 3. As the operative position of the tube holder 35 is marked by a suitable rigid abutment (not shown), the amount that the tube 37 will project into the die 107 when the tube holder 35 is in the operative position can be accurately measured and controlled by the stop gauge 139 and the micrometer 141.

Normally, when the speed controller is energized, the clutch 17 is disengaged and the brake 19 is engaged or operative to prevent the motor M-1 from driving the head 31. As described fully hereinbelow, the speed controller 21 can then be operated to energize the motor M-1 to cause the motor to operate at a predetermined minimum speed during which time the clutch remains disengaged so that the head 31 does not begin to rotate. Next, the tube 37 is inserted within the tube holder 3S and using the micrometer 141 the amount that the tube is to project from the tube holder is accurately set as described above.

The speed controller is then suitably actuated to disengage the brake 19, engage the clutch 17, and to increase the speed of the motor M-1. Thus, the motor M-l now drives the head 31 through the spindle 15.

As the speed of the motor M-1 increases, the centrifugal weights 75 and 77 pivot about their respective pivotal axis to cause movement of the flaring tool 63 radially outwardly toward the flaring surface 111 and the interior f surface of the end portion 113 of the tube 37. As the rotational speed of the head 31 increases, the flaring tool 63 contacts the end portion 113 and applies a radial outward force thereto. As the rotational speed of the head 31 increases, the magnitude of this force also increases to deform the end portion of the tube 113 radially outwardly. As the die 107 is mounted eccentrically with respect to the rotational axis of the head 31, the frictional contact between the tube 37 and the die 107 causes the die to rotate about its rotational axis. As the rotational axis of the flaring tool 63 is inclined with respect to the rotational axis of the head 31, the friction between the flaring tool 63 and the tube 37 causes the flaring tool 63 to rotate about its own rotational axis. Thus, during the flaring operation the head 31, the flaring tool 63, and the die member 107 are all simultaneously rotating about their own respective rotational axis. This provides an ironing action which assures a good surface finish. In addition, the flaring tool 63 is revolved about the rotational axis of the head 31. When the flare is completely formed,

the head will have reached a maximum speed and thereafter the speed is maintained for a short dwell time to prevent springback of the flared end portion of the tube.

At the end of the dwell time, the motor M-1 begins to decelerate and continues such deceleration until the above described minimum speed has been reached. Substantially simultaneously, with the beginning of the deceleration of the motor M-l, the clutch 17 is disengaged to drivingly disconnect the motor M-l from the head 31, and the brake 19 is applied to rapidly decelerate the head to a stop. The tube flaring operation for the tube 37 is then complete and the flared tube can be removed from the tool holder 35.

The rotational speed of the head 31 can be controlled in various ways. A preferred manner of obtaining speed control of the motor M1 and for regulating the operation of the brake 19 and the clutch 17 is shown schematically in FIG. 7.

The motor M-1, which is a DC motor with a shunted field, drives the spindle 15 provided the clutch 17 is energized. The clutch 17 is energizable by a clutch field coil 17a. The spindle 15 can be stopped by the brake 19 which is energizable by a brake field coil 19a. The operation of the circuit and the elements thereof will be explained in sequence which becomes progressively operative for the control of the tube flaring machine.

When the main power switch 210 is closed the AC voltage of the main is applied to a rectifier R-l, an auxiliary transformer T R-l, and a second auxiliary transformer TR-Z. The DC voltage developed across the rectifier bridge R1 is immediately applied to the field coil of the motor M-1. The armature of the motor M-1 is however disconnected from any source of potential so that the motor M-1 will not start to run. The transformer TR-2 is of the step-down type and its output side is connected to a second rectifier bridge R-Z to which is directly connected a potentiometer POT-1 through closed contacts 1CR-1 and ICR-2 pertaining to a relay ICR to be described more fully below. In addition, the output voltage of the rectifier R-2 is applied to the brake field coil 19a and to a capacitor C-l connected in parallel thereto. The voltage applied to the brake field coil 19a is the voltage across the capacitor C-1 gradually increasing through the adjustable potentiometer POT-1. The gradual build-up of the voltage as applied to the brake field coil 19a is not of immediate importance at this point. However, the brake field coil will be fully energized after the time constant of the C-l-POT-l RC circuit has run in order to apply the full braking force to the spindle 15.

Next in sequency of operation, a circuit switch 212 is closed. Thereupon the AC output voltage of the transformer TR42 is applied to the control circuit of a 2-phase motor M-2. The motor M-2 drives the Wiper arm of a potentiometer POT-3. This wiper arm is to be normally in the illustrated, terminal position characterized further by the fact that a limit switch LS-l in the motor control circuit is open. The motor M2 is, in addition, under control of two relay contacts 2CR-1 and ZCR-Z pertaining to a relay ZCR which at this point is not energized. The contact 2CR-1 is normally closed and the contact 2CR-2 is normally open. In this case, therefore, the one field winding of the motor M-2 would be energizable only if the limit switch LS-1 were also closed. This will not lbe the case if the wiper arm for potentiometer POT-3 has the desired, initial position. Should, however, this not be the case, then the wiper arm will not have caused the limit switch LS-l to open so that the two contacts LS-l and 2CR-1 are both closed and motor M-Z will run. The particular winding of the Z-phase motor then energized will cause the wiper arm of POT-3 to be placed in such a position that the contact of limit switch LS-l will be opened whereupon the motor M-2 is at rest. One can therefore see that by closing switch 212 the control circuit for motor M-Z causes potentiometer 9 POT-3 automatically to be placed into the initial position should that not be the case.

Next, the motor start switch 214 is closed causing the relay FC to energize. The contact FC-l of relay FC closes so that the relay FC can hold over its own circuit. The contact FC-2 of relay FC also closes causing the motor control relay FOR to be energized. Two normally open contacts FOR-1 and FOR-3 close and respectively connect the armature of motor M-1 to the negative pole of the rectifier R-1 and to the output line MA-l of a magnetic amplifier MAG AMP. The magnetic amplifier is not shown in detail and is of a conventional design. -It includes one or several feed-back control windings which connect line MA-l to a line MA-Z which in turn connects to the interconnected cathodes of a pair of Thyratrons TH-l and 'FH-2. Thus, contact FOR-3 connects the one motor terminal to the interconnected cathodes of the two Thgyratrons. The interconnected cathodes of the two Thyratrons form Wha-t can be described best, as a terminal for a controlled positive potential for the motor M-l. The anodes of the Thyratrons TH-l and TH-Z are respectively connected to the two AC input terminals of the rectifier R-1. Therefore, the interconnected cathodes of the Thyratrons TH-l and TH-2 on one hand and the negative terminal of the rectifier bridge R-l form a second source for a DC voltage to which is now connected the armature of motor M-l, through a feed-back winding in the magnetic amplifier included in that circuit.

The magnetic amplifier has a control input line MA-3 with a return path MA-4 leading to the positive terminal of the rectifier R-l. Upon response of relay FC, a contact FC-4 opens the control windings in the MAG AMP and connected in between the lines MA-3 and MA- 4 and thus come under the influence of an RC circuit RC-l. The charge current for the capacitor circuit RC-l determines the state of the magnetic amplifier. This, however, is a transient phenomenon, and the control current decays when the capacitor of the RC circuit RC-l is charged.

The magnetic amplifier has two output circults, one leading into a line MA-S, the other into a line MA-6. The line MA-S is connected to the grid of the Thyratron TH-l, the line MA-G is connected to the grid of the Thyratron TH2. The magnetic amplifier is now adjusted so that at first, with a peak current flowing into the capacitor of the RC circuit RC-l the control of the Thyratrons TH-1 and TH-Z provide for early firmg 1n relation to the phase of the AC input applied across anodes and cathodes so that full voltage is applied to the line MA-Z for a rapid start of the motor M-l. In addition it should be mentioned that upon response of the relay FOR, the contact lFOR--Z opens so that the brake circuit for the motor M-l is deactivated.

The motor M-1 is therefore subjected to a current burst to start up rapidly. The decay of the control current in the line MA-3-MA-4 is controlled by the RC circuit RC-l, causing the firing angle for Thyratrons to be shifted toward a greater relative delay and the voltage applied to the armature of the motor M-1 decreases. The control line MA-S for the magnetic amplifier MAG AMP also comes under the control of a circuit network upon response of relay FC by closing of the contact IFC-3 thereof. This circuit network comprises three potentiometers POT-6, POTA and POT-5. It is not effective initially because the steep pulses produced by the RC circuit RC-l for the lines MA-3 and MA-4 overrides the potentiometer network. Upon decay of that pulse the potentiometer network takes over. The circuit connection is made so that for the initial setting of potentiometer POT-3 the current flowing into the line MA-S is predominantly determined by the' potentiometer POT-4. The adjustment of the potentiometer POT-5 has very little influence at that point. The control current now produced for the MAG AMP is adjusted by the potentiometer POT-4 and is flowing into the wiper thereof and into the wiper of POT-S in the' particular terminal position as explained above.

The magnetic amplifier is controlled so that the phase angle of the firing pulse's for the Thyratrons TH-l and TH-2 is rather delayed and the DC output voltage at the interconnected cathodes of the Thyratrons is rather low, so that ultimately the motor M-l stabilizes at a minimum speed. The particular minimum speed is adjustable by the potentiometer POT-4. After some time, particularly after the motor M-1 has stabilized to run at the minimum speed as adjusted by the potentiometer POT-4, the cycle switch 212 is closed. The cycle switch 212 when closed connects the variable timer to the secondary winding of transformer TR-2 with the immediate effect of closing of contact T-l. In addition, the timer now begins to run and in accordance with its adjusted time constant it will maintain the contact T-1 closed for the adjusted period of time.

Upon closing of contact T-1 relays 1CR and 2CR are energized. The relay ZCR when energized through the closed contact T-1 opens the contact 2CR-1 and encloses the contact 2CR-2. Thereupon a particular circuit is established for the second winding of the 2-phase motor M-Z because the limit switch LS-Z connected in series with the contact 2CR-2 is closed. The motor M-2 begins to run in a direction opposite to the one explained above causing the wiper arm of the potentiometer POT-3 to move and to gradually place the resistance of the potentiometer POT-3 into the control circuit for the magnetic amplifier. The current in the lines MA-3-MA-4 changes accordingly and the control signals for the grids of Thyratrons TH-l and TH-Z are gradually shifted so that the average DC potential at the interconnected cathodes of the two Thyratrons increases. In accordance with this gradually increased voltage as applied to the armature of motor M-l, the motor M-l begins to rotate at a higher speed.

After the wiper arm has assumed the second terminal position, the potentiometer POT-3 is completely inserted into the control circuit for the control windings of the magnetic amplifier, and limit switch LS-2 responds, i.e. it opens and the motor M-2 stops. The system stabilizes and the motor M-l will now run at a maximum speed determined by the control current then owing into the control windings of the magnetic amplifiers. This control current is adjusted essentially by the position of the wiper arm of potentiometer POT-5. It is assumed that the potentiometers POT-3 and POT-5 have considerable higher resistance than the" total resistance of the potentiometer POT-4 so that the adjustment of potentiometer POT-4 is not influential any more on the current flowing now into the control circuit MA-3-MA-4 for the magnetic amplifier.

The position of the potentiometer POT-5 is also influential in the rate of change of the control current during the period when the wiper arm of potentiometer POT-3 sweeps over the potentiometer POT-3 as with this sweep the potentiometer POT-5 also becomes increasingly influential in this circuit for the control windings of the magnetic amplifier. The adjustment of potentiometer POT-5 determines the ultimate or maximum speed of the motor M-1 as well as the rate at which that speed is obtained, because the period of time it takes the wiper to move across potentiometer POT-3 from one terminal position to the other one is a fixed one and may be about 8 seconds.

The motor M-l will now rotate at the adjusted maximum speed from the time that the wiper reaches the terminal position adjacent switch LS-2 until the timer has run. This may be for about 2 seconds.

Before describing the result of the running of the timer it should be mentioned that upon initial response, i.e., upon closing of the switchc T-l which caused the motor M-2 to run for controlling an increase of the speed of 11 the motor M-1, the relay 1CR also responded. This occurs at more or less precisely the moment when the motor M-1 begins to increase its speed from the minimum speed it has obtained initially. Upon response of the relay ICR the contacts ICR-1 and ICR-2 open and remove voltage from the brake field coil 19a, thus releasing the brake.

Another pair of contacts ICR-3 and ICR-4, also under the control of relay ICR, close and cause the capacitor C-2 to be charged. Potentiometer POT-2 is adjusted to determine the rate of the gradual increase of the voltage across the capacitor C-Z which is effective at the clutch field coils 17a. Therefore, the clutch is energized gradually to drivingly connect the motor M-1 to the head 31 as the motor M-l begins to increase its speed. The time constant as defined by elements C-2 and POT-2 however is adjusted so that the clutch is fully energized before the motor M-1 has obtained maximum speed. Thus, the tube 37 is flared during the time that the speed of the motor M-1 is increasing.

After the time constant of the timer has run, contact T-1 opens and relays ICR and 2CR deenergize. Accordingly, the contacts ICR-3 and ICR-4 open, the clutch field 17a deenergizes and in effect decouples the head 31 from the motor Mel. In addition, the contact ICR-1 and ICR-2 close and the capacitor C-1 charges through the POT-1 at a rate adjusted by the POT-1. The voltage across the capacitor C-1 is gradually effective across the brake field coil 19a so that the gradual braking force is applied to the head 31. That situation is maintained until such time that the relay ICR again is energized.

The deenergization of the relay ZCR causes closing of the contact 2CR-1 and opening of the contact 2CR-2. Limit switch LS-1 closes as soon as the wiper arm of potentiometer POT-3 moved out of the initial illustrated position and maintained closed thereafter. After closing of contact 2CR-1 a circuit for the first mentioned winding of motor M-2 is established causing the motor to run in a direction to return the wiper arm of potentiometer POT-3 to the initial position. It is apparent from the foregoing that this gradually changes the current in the control windings of the magnetic amplifier connected to the lines MA-3 and MA-4, the firing angle for the Thyratrons becomes gradually more delayed and the motor M1 will accordingly reduce its speed. After the wiper arm of POT-3 has returned to the initial position, limit switch LS-1 opens, motor M-2 stops and very soon thereafter the motor M-1 will run again at minimum speed. The cycle switch 212 is opened thereafter which causes the timer to be reset to obtain an operating state requiring closing of switch 216 for another timing cycle. Cycle switch 216 will be closed again as soon as a new work piece has ben placed into the die 107.

Upon opening of a motor stop switch 218 relays FC and FOR are deenergized, the armature of motor M-1 is disconnected from the various sources of potential and resistor is connected across the armature by the closing of the contact FOR-2 for a complete deenergization of the motor M-1 so that the motor will remain at rest. The field winding will remain energized until such time that the power switch is open.

Although exemplary embodiments of the invention have been shown and described, many changes, modifications, and substitutions may be made by one having ordinary skill in the art without necessarily departing from the spirit and scope of this invention.

I claim:

1. In a machine for flaring an end portion of a tube wherein the end portion has an interior surface, the combination of:

a die having an opening therein for receiving the end portion of the tube to be flared, said die having a flaring surface disposed generally radially outwardly of the end portion of the tube for assisting in flaring the end portion;

a flaring tool extendable into the interior of the end portion of the tube;

means for mounting said flaring tool for movement generally radially outwardly toward said flaring surface;

an electric motor;

speed control means for regulating the speed of the electric motor to permit a gradual increase in the speed of said electric motor;

means for drivingly connecting said electric motor and said flaring tool to permit said electric motor to move said flaring tool generally radially outwardly to apply a generally radial outward force against the interior surface of the end portion of the tube, the magnitude of which increases with an increase in the speed of the electric motor; and

means for rotating said flaring tool relative to said die while said flaring tool is moving radially outwardly to flare the end portion of the tube.

2. A combination as defined in claim 1 wherein said speed control means includes adjustable means for permitting increasing the speed of said electric motor at a plurality of rates to thereby permit adjustment of the rate of change of magnitude of said force applied to the end portion of the tube whereby the machine is readily adapted for use with tubes of varying flaring characteristics.

3. A combination as defined in claim 1 wherein said speed control means includes means for increasing the speed of the motor to a given maximum to at least substantially completely flare the end portion of the tube and means for thereafter maintaining motor speed substantially constant for the period of time required to substantially reduce the tendency of the flared end portion to spring back toward its original position.

4. A combination as defined in claim 1 wherein the motor speed can be increased up to a maximum value and including means for adjusting said maximum value.

5. A combination as defined in claim 1 including clutch means for drivingly disconnecting said electric motor from said flaring tool and wherein said speed control means includes means for maintaining the speed of said motor at a minimum value.

6. A combination as defined in claim 5 wherein clutch means drivingly connect said electric motor and said flaring tool and means are provided for automatically engaging said clutch means when the speed of said motor rises at about said minimum speed.

7. In a machine for flaring an end portion of a tube wherein the end portion has an interior surface, the combination of a die member having an opening therein for receiving the end portion of the tube to be flared, said die having a flaring surface surrounding the end portion of the tube for assisting in flaring the end portion;

a flaring tool member extendable into the interior of the end portion of the tube, said flaring tool mem- -ber having a working surface;

means for mounting at least one of said members to permit relative movement of said flaring surface and said working surface toward each other to deform the end portion of the tube radially outwardly;

first electric motor means drivingly connected to said one member to move said one member to apply a flaring force against the end portion of the tube, the magnitude of which increases with an increase in the speed of the electric motor;

second motor means; and

means driven by said second motor means for gradually increasing the speed of said motor means to thereby gradually increase the magnitude of said flaring force.

8. A combination as defined in claim 7 wherein said last mentioned means includes a potentiometer having a 13 wiper driven by said second motor means to produce a control signal which is a function of the position on said wiper and means responsive to said control signal for varying the speed of said first motor means.

9. A combination as dened in claim 7 wherein said first motor means is a DC motor and said last mentioned means gradually increased the voltage supply to said first motor means to thereby increase the speed thereof.

10. In a machine for flaring an end portion of a tube wherein the end portion has an interior surface, the combination of:

a die member having an opening therein for receiving the end portion of the tube to be tlared, said die having a llaring surface surrounding the end portion of the tube for assisting in llaring t-he end portion;

a ilaring tool member extendable into the interior of the end portion ofthe tube, said ilaring tool member having a working surface;

means for mounting at least one of said members to permit relative movement of said flaring surface and said working surface toward each other to deform the end portion of the tube radially outwardly;

varia-ble speed electric motor means drivingly connected to said one member to move said one member to apply a llaring force against the end portion of the tube with a magnitude which increases with an increase in the speed ofthe electric motor;

means for operating said electric motor means at a minimum speed;

means for accelerating said motor means from said minimum speed to a maximum speed to gradually increase the magnitude of the flaring force; and

means for causing relative rotation between said flaring tool member and said die member while said flaring force is being applied to the end portion of the tube to flare the tube.

11. A combination as defined in claim 10 including means for maintaining motor speed at said maximum speed for a predetermined interval.

12. A combination as defined in claim 10 including:

a clutch engageable to drivingly connect said motor means and said one member;

means for disengaging said clutch when said motor -means is operating at said minimum speed; and

means for engaging said clutch at about the time that said motor means begins to accelerate from said minimum speed.

13. A combination as defined in claim 10 including means for selectively adjusting the rate of acceleration of said motor means and means `for selectively adjusting said maximum speed.

14. 'In a machine for flaring an end portion of a tube having an interior surface, the combination of:

a die having an opening therein for receiving the end portion of the tube to be flared, said die having a flaring surface radially outwardly of the end portion of the tube for assisting in ilaring the end portion;

means for mounting said die for rotation;

a rotatable head;

means for mounting said head for rotation adjacent said die;

said head including a ilaring tool extendable into the interior of the end portion of' the tube and centrifugal means responsive to rotation of the head for moving the llaring tube generally radially outwardly into contact with the end portion of the tube to apply a force thereto, the magnitude of which is a function of the rotational speed of the head;

variable speed motor means drivingly connected to said head for rotating said head to operate said centrifugal means for moving the flaring tool generally radially outwardly; and

speed control means for varying the speed at which said motor means operates to thereby permit regulation of the force applied by said flaring tool to the end portion of the tube.

15. A combination as defined in claim 14 including a stop member mounted on said head for fixing the outer- 10 most radial position to which the flaring tool can be moved by the centrifugal means.

16. A combination as ydefined in claim 14 wherein said die is mounted on said head for rotation relativev thereto and means, are provided for adjusting the radial position l5 of the die relative to the head to compensate for the allowable tolerance of the tubes.

17. A combination as deiined in claim 14 including:

tube holding means for holding the end portion of the tube within the die;

means for moving said tube holding means between an operative position in which the end portion of the tube is inserted within the die and an inoperative position in which the end portion of the tube is withdrawn from the die; and

micrometer means mounted on said tube holding means for measuring the amount that the end portion of the tube will project into the die in said operative position.

30 18. In a machine for flaring an end portion of a tube having an interior surface, the combination of a supporting structure;

a die mounted on the supporting structure and having an opening therein for receiving the end portion of the tube to be flared, said die having a ilaring surface radially outwardly of the end portion of the tube for assisting in flaring the end portion;

means for mounting said die for rotation relative to the supporting structure;

tube mounting means mounted on the supporting structure for holding the end portion of the tube rwithin |the die;

means on the supporting structure for mounting said tube mounting means for movement between an operative position in which the end portion of the tube is inserted within the die and a retracted position in which the end portion of the tube is at least partially withdrawn from the die, the position of the tube relative to the tube mounting means in the retracted position determining the extent to which the end portion of the tube will project into the die in said operative position; stop gauge movably mounted on said supporting structure and having a tube adjusting surface, the tube being movable in the tube mounting means until the end portion of the tube engages the adjusting surface to thereby tix the extent to which the end portion of the tube will project into the die; means deiining a reference surface;

a measuring device, one of said measuring device and reference surface being carried by said stop gaugesaid measuring Vdevice and stop gauge being engageable when the tube is in said retracted position, said measuring device including adjustable means for adjusting the distance between the reference surface `and the stop gauge to thereby adjust the position of the adjuting surface, said adjusting means being calibrated so that the amount the end portion of the tube will project into the die can be measured by said adjustable means.

19. A combination as defined in claim 18 wherein said 75 tube mounting means includes a chuck for holding the 15 tube, said reference surface is on said chuck and said measuring device is carried by said stop gauge.

20. A combination as defined in claim 18 wherein said reference surface includes first and second reference surface portions on the tube mounting means and supporting structure, respectively, both of said surface portions being usable to adjust the position of the adjusting surface and means for mounting the stop gauge for movement so that the measuring device can engage either of said surface portions.

l 6 References Cited UNITED STATES PATENTS Re. 26,231 `6/1967 Groth 72-123 1,775,766 9/1930 Holmes 72-123 CHARLES W. LANHAM, Primary Examiner LOWELL A. LARSON, Assistant Examiner U.S. Cl. X.'R. 

